During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from the double 14-cm "Cassius" telescope in Cerro Tololo, Chile, we discovered a new bright transient source, most likely a supernova, in the galaxy IC 4303.

ASASSN-15kz was discovered in images obtained on UT 2015-06-12.07 at V~15.9 mag. We do not detect (V>17.0) the object in images taken on UT 2015-06-08.11 and before. Images obtained by S. Kiyota on UT 2015-06-12.43 using a 0.5m CDK + FLI PL-9000 at the ITelescope.NET site at Siding Springs Observatory and by J. Brimacombe on UT 2015-06-12.64 with the CDK 43-cm telescope at Savannah Skies Observatory confirm the discovery of the transient. This figure shows the archival DSS image of the host (left) and the S. Kiyota confirmation image (right). The red circle has a radius of 4" and is centered on the position of the transient in the S. Kiyota image.

The position of ASASSN-15kz is approximately 5.2" North and 6.0" East from the center of the galaxy IC 4303 (z=0.008022, d=37.1 Mpc, via NED), giving an absolute V-band magnitude of approximately -17.1 (m-M=32.86, A_V=0.165). Properties of the new source and photometry are summarized in the tables below:

We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported in part by Mt. Cuba Astronomical Foundation. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.